Silly question, but is wind at sea guaranteed? What if weather patterns change? It's really expensive to put up these offshore turbines, but with systemic climate change is it possible they'd be becalmed?
So, yes, it's so likely that it's practically guaranteed. Too much wind is an orders of magnitude more likely problem.
It's worth elaborating that too much wind is as bad as too little wind. The blades can only spin so fast before disintegrating, so wind turbines have transmissions and choose a gear appropriate to the current wind speed. Once wind speeds exceed what the highest gear can handle the turbine locks the blades to prevent damage. In that state it doesn't produce any electricity.
Larger turbines are more productive especially at lower wind speeds as far as I know.
They are more expensive than on-shore wind turbines, but still significantly cheaper than other forms of generation (such as nuclear).
With geographic and technological diversity, "smart grid" demand management, inter-connectors, storage tech, and a modest investment in nuclear baseload, we can get pretty close to 100% low-carbon generation in the UK over the next few decades. Even as grid demand increases with the gradual electrification of heating and transport.
Onshore and offshore wind, Nuclear (all mentioned), solar, hydro. As far as I'm aware all the good hydro sites in Britain have been used up, so there's only solar that really should have been mentioned.
Off shore wind is probably more expensive that solar, does that really change the parents point?
Most of that is from the sea.
Worst case scenario for Britain would be a period of little wind in the North sea, in Winter. That would be unusual, but not unheard of.
I'm not aware of any plausible scenarios where global warming would lead to less wind, but I suppose its locally possible.
The trade winds are pretty consistent.
My favourite bit of meteorology trivia is that the wealthier areas in British cities are almost exclusively to the west - this is because the prevailing wind is from the west and so pollution producing factories have been placed in the east of the city.
You can even split wind into onshore and offshore, although the data is patchy.
Wind varies, but from a quick look offshore hasn't gone to zero over the past year and neither has onshore.